Eleven in Old English is endleofan, and related forms in the various Germanic languages point back to an original Germanic *ainlif, "eleven." *Ainlif is composed of *ain-, "one," the same as our one, and the suffix *-lif from the Germanic root *lib-, "to adhere, remain, remain left over." Thus, eleven is literally "one-left" (over, that is, past ten), and twelve is "two-left" (over past ten).
Hmmm. Interesting. I think from now on I'm going to say "endleofan" instead of "eleven". Maybe I can start a trend toward a more interesting way to express "eleven". (If anyone asks me why I say it that way I'll just say, "I don't know. Isn't that the way everyone says it?"
I can't explain that, but one that's even more disturbing (and fortunately, for my sanity, not too many people say this) is, "Fi dollars" (instead of "five dollars"). If anyone reading here says, "Fi dollars" - STOP!! Also, if anyone says "twony" - really! STOP!!